1、 准备两个待合并的映射表，示例中通过新建获取，实际应用时应从数据库或其它数据源读取所需数据。 2、 调用putAll方法合并map时，需先判断对象是否为null。为避免map01为null导致无法合并map02，应新建一个map实例来确保操作顺利执行。

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